Issue #8: add grpc authentication and scope authorization

Verified with dotnet build src\\MxGateway.sln and dotnet test src\\MxGateway.sln.

docs/gateway-process-design.md

@@ -612,6 +612,15 @@ hashes the presented secret, and compares the stored and presented hashes with
 results distinguish malformed credentials, missing keys, revoked keys, missing
 pepper configuration, and hash mismatch for internal authorization handling.
 
+`GatewayGrpcAuthorizationInterceptor` enforces this authentication model for
+public gRPC calls. Missing, malformed, revoked, unknown, or mismatched keys fail
+with `Unauthenticated`. Authenticated calls missing the scope required by the
+RPC fail with `PermissionDenied`. The interceptor applies to unary calls and
+server-streaming calls and stores the authenticated `ApiKeyIdentity` in
+`IGatewayRequestIdentityAccessor` for the duration of the request handler.
+`Authentication:Mode` set to `Disabled` bypasses API-key verification for local
+development only.
+
 Recommended scopes:
 
 - `session:open`
@@ -631,6 +640,23 @@ gRPC admin API. It should initialize the auth database, create keys, list keys
 without secrets, revoke keys, rotate keys, and print raw secrets only once at
 creation.
 
+`MxGateway.Server` exposes local API-key administration as an `apikey`
+subcommand before the web host starts:
+
+```bash
+MxGateway.Server apikey init-db --sqlite-path C:\ProgramData\MxGateway\gateway-auth.db
+MxGateway.Server apikey create-key --key-id operator01 --display-name Operator --scopes session:open,events:read
+MxGateway.Server apikey list-keys --json
+MxGateway.Server apikey revoke-key --key-id operator01
+MxGateway.Server apikey rotate-key --key-id operator01 --json
+```
+
+The subcommands accept `--sqlite-path`, `--pepper`, and `--json`. `--pepper`
+sets the local `MxGateway:ApiKeyPepper` configuration value for the command
+process; deployments should normally provide the pepper through the configured
+secret source. `create-key` and `rotate-key` print the full raw API key exactly
+once. `list-keys` never prints raw secrets or `secret_hash` values.
+
 SQLite auth storage should use startup migrations with a `schema_version` table.
 Migrations should run inside transactions and fail startup if the database
 schema is newer than the running binary understands.
@@ -660,6 +686,20 @@ Commands requiring authorization:
 - worker shutdown diagnostics,
 - metadata queries if they expose sensitive plant structure.
 
+Current gRPC scope mapping:
+
+- `OpenSession` requires `session:open`.
+- `CloseSession` requires `session:close`.
+- `StreamEvents` and `DrainEvents` require `events:read`.
+- read-style MXAccess commands such as `Register`, `AddItem`, `Advise`, and
+  `Ping` require `invoke:read`.
+- `Write` and `Write2` require `invoke:write`.
+- `WriteSecured`, `WriteSecured2`, and `AuthenticateUser` require
+  `invoke:secure`.
+- metadata commands such as `ArchestrAUserToId`, `GetSessionState`, and
+  `GetWorkerInfo` require `metadata:read`.
+- `ShutdownWorker` requires `admin`.
+
 ### Worker IPC
 
 Named pipes should be local only. Pipe ACLs should restrict access to:
@@ -802,6 +842,9 @@ workers and fake transports.
 Focused tests:
 
 - session state transitions,
+- gRPC API-key authentication for unary and streaming calls,
+- gRPC scope mapping for sessions, invokes, events, metadata, and admin
+  commands,
 - worker startup failures,
 - protocol version mismatch,
 - malformed frame handling,

gateway.md

@@ -566,9 +566,13 @@ Because each client owns one worker, a crash or leak affects only that session.
 External gateway:
 
 - use TLS for remote gRPC if crossing machine boundaries,
-- authenticate clients with Windows auth, mTLS, or a deployment-specific token,
-- authorize access to commands that can write, authenticate users, or alter
-  runtime state.
+- authenticate v1 gRPC clients with `authorization: Bearer
+  mxgw_<key-id>_<secret>` API-key metadata,
+- reject missing or invalid API keys with gRPC `Unauthenticated`,
+- reject valid keys that lack the required session, invoke, event, metadata, or
+  admin scope with gRPC `PermissionDenied`,
+- authorize access to commands that can write, authenticate users, expose
+  metadata, stream events, or alter runtime state.
 
 Internal worker IPC:
 

src/MxGateway.Server/GatewayApplication.cs

@@ -3,6 +3,7 @@ using MxGateway.Server.Configuration;
 using MxGateway.Server.Diagnostics;
 using MxGateway.Server.Metrics;
 using MxGateway.Server.Security.Authentication;
+using MxGateway.Server.Security.Authorization;
 using MxGateway.Server.Workers;
 
 namespace MxGateway.Server;
@@ -26,6 +27,7 @@ public static class GatewayApplication
 
         builder.Services.AddGatewayConfiguration();
         builder.Services.AddSqliteAuthStore();
+        builder.Services.AddGatewayGrpcAuthorization();
         builder.Services.AddHealthChecks();
         builder.Services.AddSingleton<GatewayMetrics>();
         builder.Services.AddWorkerProcessLauncher();

src/MxGateway.Server/MxGateway.Server.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Grpc.AspNetCore" Version="2.76.0" />
     <PackageReference Include="Microsoft.Data.Sqlite" Version="10.0.7" />
   </ItemGroup>
 

src/MxGateway.Server/Program.cs

@@ -1,7 +1,43 @@
 using MxGateway.Server;
+using MxGateway.Server.Configuration;
+using MxGateway.Server.Security.Authentication;
 
-var app = GatewayApplication.Build(args);
+ApiKeyAdminParseResult apiKeyAdminCommand = ApiKeyAdminCommandLineParser.Parse(args);
+if (apiKeyAdminCommand.IsApiKeyCommand)
+{
+    if (apiKeyAdminCommand.Command is null)
+    {
+        await Console.Error.WriteLineAsync(apiKeyAdminCommand.Error);
+        return 2;
+    }
+
+    WebApplicationBuilder builder = GatewayApplication.CreateBuilder([]);
+    ApplyApiKeyAdminOverrides(builder.Configuration, apiKeyAdminCommand.Command);
+    await using WebApplication cliApp = builder.Build();
+    await using AsyncServiceScope scope = cliApp.Services.CreateAsyncScope();
+
+    ApiKeyAdminCliRunner runner = scope.ServiceProvider.GetRequiredService<ApiKeyAdminCliRunner>();
+
+    return await runner.RunAsync(apiKeyAdminCommand.Command, Console.Out, CancellationToken.None);
+}
+
+WebApplication app = GatewayApplication.Build(args);
 
 app.Run();
 
+return 0;
+
+static void ApplyApiKeyAdminOverrides(IConfiguration configuration, ApiKeyAdminCommand command)
+{
+    if (!string.IsNullOrWhiteSpace(command.SqlitePath))
+    {
+        configuration[$"{GatewayOptions.SectionName}:Authentication:SqlitePath"] = command.SqlitePath;
+    }
+
+    if (!string.IsNullOrWhiteSpace(command.Pepper))
+    {
+        configuration["MxGateway:ApiKeyPepper"] = command.Pepper;
+    }
+}
+
 public partial class Program;

src/MxGateway.Server/Security/Authentication/ApiKeyAdminCliRunner.cs

@@ -0,0 +1,180 @@
+using System.Text.Json;
+
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed class ApiKeyAdminCliRunner(
+    IAuthStoreMigrator migrator,
+    IApiKeyAdminStore adminStore,
+    IApiKeyAuditStore auditStore,
+    IApiKeySecretHasher hasher)
+{
+    private static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        WriteIndented = true
+    };
+
+    public async Task<int> RunAsync(
+        ApiKeyAdminCommand command,
+        TextWriter output,
+        CancellationToken cancellationToken)
+    {
+        ApiKeyAdminOutput result = command.Kind switch
+        {
+            ApiKeyAdminCommandKind.InitDb => await InitDbAsync(cancellationToken).ConfigureAwait(false),
+            ApiKeyAdminCommandKind.CreateKey => await CreateKeyAsync(command, cancellationToken).ConfigureAwait(false),
+            ApiKeyAdminCommandKind.ListKeys => await ListKeysAsync(cancellationToken).ConfigureAwait(false),
+            ApiKeyAdminCommandKind.RevokeKey => await RevokeKeyAsync(command, cancellationToken).ConfigureAwait(false),
+            ApiKeyAdminCommandKind.RotateKey => await RotateKeyAsync(command, cancellationToken).ConfigureAwait(false),
+            _ => throw new InvalidOperationException($"Unsupported API key command '{command.Kind}'.")
+        };
+
+        await WriteOutputAsync(command, result, output).ConfigureAwait(false);
+
+        return 0;
+    }
+
+    private async Task<ApiKeyAdminOutput> InitDbAsync(CancellationToken cancellationToken)
+    {
+        await migrator.MigrateAsync(cancellationToken).ConfigureAwait(false);
+        await AppendAuditAsync(null, "init-db", null, cancellationToken).ConfigureAwait(false);
+
+        return new ApiKeyAdminOutput("init-db", "initialized", null, []);
+    }
+
+    private async Task<ApiKeyAdminOutput> CreateKeyAsync(
+        ApiKeyAdminCommand command,
+        CancellationToken cancellationToken)
+    {
+        await migrator.MigrateAsync(cancellationToken).ConfigureAwait(false);
+
+        string keyId = Required(command.KeyId);
+        string secret = ApiKeySecretGenerator.Generate();
+        string apiKey = FormatApiKey(keyId, secret);
+
+        await adminStore.CreateAsync(
+                new ApiKeyCreateRequest(
+                    KeyId: keyId,
+                    KeyPrefix: $"mxgw_{keyId}",
+                    SecretHash: hasher.HashSecret(secret),
+                    DisplayName: Required(command.DisplayName),
+                    Scopes: command.Scopes,
+                    CreatedUtc: DateTimeOffset.UtcNow),
+                cancellationToken)
+            .ConfigureAwait(false);
+        await AppendAuditAsync(keyId, "create-key", null, cancellationToken).ConfigureAwait(false);
+
+        return new ApiKeyAdminOutput("create-key", "created", apiKey, []);
+    }
+
+    private async Task<ApiKeyAdminOutput> ListKeysAsync(CancellationToken cancellationToken)
+    {
+        await migrator.MigrateAsync(cancellationToken).ConfigureAwait(false);
+        IReadOnlyList<ApiKeyRecord> keys = await adminStore.ListAsync(cancellationToken).ConfigureAwait(false);
+        await AppendAuditAsync(null, "list-keys", null, cancellationToken).ConfigureAwait(false);
+
+        return new ApiKeyAdminOutput(
+            "list-keys",
+            "ok",
+            null,
+            keys.Select(ToListedKey).ToArray());
+    }
+
+    private async Task<ApiKeyAdminOutput> RevokeKeyAsync(
+        ApiKeyAdminCommand command,
+        CancellationToken cancellationToken)
+    {
+        await migrator.MigrateAsync(cancellationToken).ConfigureAwait(false);
+
+        string keyId = Required(command.KeyId);
+        bool revoked = await adminStore.RevokeAsync(keyId, DateTimeOffset.UtcNow, cancellationToken)
+            .ConfigureAwait(false);
+
+        await AppendAuditAsync(keyId, "revoke-key", revoked ? "revoked" : "not-found-or-already-revoked", cancellationToken)
+            .ConfigureAwait(false);
+
+        return new ApiKeyAdminOutput("revoke-key", revoked ? "revoked" : "not-found-or-already-revoked", null, []);
+    }
+
+    private async Task<ApiKeyAdminOutput> RotateKeyAsync(
+        ApiKeyAdminCommand command,
+        CancellationToken cancellationToken)
+    {
+        await migrator.MigrateAsync(cancellationToken).ConfigureAwait(false);
+
+        string keyId = Required(command.KeyId);
+        string secret = ApiKeySecretGenerator.Generate();
+        string apiKey = FormatApiKey(keyId, secret);
+
+        bool rotated = await adminStore.RotateAsync(keyId, hasher.HashSecret(secret), DateTimeOffset.UtcNow, cancellationToken)
+            .ConfigureAwait(false);
+
+        await AppendAuditAsync(keyId, "rotate-key", rotated ? "rotated" : "not-found", cancellationToken)
+            .ConfigureAwait(false);
+
+        return new ApiKeyAdminOutput("rotate-key", rotated ? "rotated" : "not-found", rotated ? apiKey : null, []);
+    }
+
+    private static async Task WriteOutputAsync(
+        ApiKeyAdminCommand command,
+        ApiKeyAdminOutput result,
+        TextWriter output)
+    {
+        if (command.Json)
+        {
+            await output.WriteLineAsync(JsonSerializer.Serialize(result, JsonOptions)).ConfigureAwait(false);
+            return;
+        }
+
+        await output.WriteLineAsync($"{result.Command}: {result.Status}").ConfigureAwait(false);
+
+        if (result.ApiKey is not null)
+        {
+            await output.WriteLineAsync($"API key: {result.ApiKey}").ConfigureAwait(false);
+        }
+
+        foreach (ApiKeyAdminListedKey key in result.Keys)
+        {
+            string revoked = key.RevokedUtc is null ? "active" : "revoked";
+            await output.WriteLineAsync($"{key.KeyId}\t{key.DisplayName}\t{revoked}\t{string.Join(',', key.Scopes)}")
+                .ConfigureAwait(false);
+        }
+    }
+
+    private async Task AppendAuditAsync(
+        string? keyId,
+        string eventType,
+        string? details,
+        CancellationToken cancellationToken)
+    {
+        await auditStore.AppendAsync(
+                new ApiKeyAuditEntry(
+                    KeyId: keyId,
+                    EventType: eventType,
+                    RemoteAddress: null,
+                    Details: details),
+                cancellationToken)
+            .ConfigureAwait(false);
+    }
+
+    private static ApiKeyAdminListedKey ToListedKey(ApiKeyRecord key)
+    {
+        return new ApiKeyAdminListedKey(
+            KeyId: key.KeyId,
+            KeyPrefix: key.KeyPrefix,
+            DisplayName: key.DisplayName,
+            Scopes: key.Scopes,
+            CreatedUtc: key.CreatedUtc,
+            LastUsedUtc: key.LastUsedUtc,
+            RevokedUtc: key.RevokedUtc);
+    }
+
+    private static string FormatApiKey(string keyId, string secret)
+    {
+        return $"mxgw_{keyId}_{secret}";
+    }
+
+    private static string Required(string? value)
+    {
+        return value ?? throw new InvalidOperationException("Required command value was not provided.");
+    }
+}

src/MxGateway.Server/Security/Authentication/ApiKeyAdminCommand.cs

@@ -0,0 +1,10 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed record ApiKeyAdminCommand(
+    ApiKeyAdminCommandKind Kind,
+    bool Json,
+    string? SqlitePath,
+    string? Pepper,
+    string? KeyId,
+    string? DisplayName,
+    IReadOnlySet<string> Scopes);

src/MxGateway.Server/Security/Authentication/ApiKeyAdminCommandKind.cs

@@ -0,0 +1,10 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public enum ApiKeyAdminCommandKind
+{
+    InitDb,
+    CreateKey,
+    ListKeys,
+    RevokeKey,
+    RotateKey
+}

src/MxGateway.Server/Security/Authentication/ApiKeyAdminCommandLineParser.cs

@@ -0,0 +1,159 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public static class ApiKeyAdminCommandLineParser
+{
+    public static ApiKeyAdminParseResult Parse(IReadOnlyList<string> args)
+    {
+        if (args.Count == 0 || !string.Equals(args[0], "apikey", StringComparison.OrdinalIgnoreCase))
+        {
+            return ApiKeyAdminParseResult.NotApiKeyCommand();
+        }
+
+        if (args.Count < 2)
+        {
+            return ApiKeyAdminParseResult.Fail("Missing apikey subcommand.");
+        }
+
+        if (!TryParseKind(args[1], out ApiKeyAdminCommandKind kind))
+        {
+            return ApiKeyAdminParseResult.Fail($"Unknown apikey subcommand '{args[1]}'.");
+        }
+
+        Dictionary<string, string?> options = new(StringComparer.OrdinalIgnoreCase);
+        bool json = false;
+
+        for (int index = 2; index < args.Count; index++)
+        {
+            string arg = args[index];
+            if (string.Equals(arg, "--json", StringComparison.OrdinalIgnoreCase))
+            {
+                json = true;
+                continue;
+            }
+
+            if (!arg.StartsWith("--", StringComparison.Ordinal))
+            {
+                return ApiKeyAdminParseResult.Fail($"Unexpected argument '{arg}'.");
+            }
+
+            string name = arg[2..];
+            string? value;
+
+            int equalsIndex = name.IndexOf('=', StringComparison.Ordinal);
+            if (equalsIndex >= 0)
+            {
+                value = name[(equalsIndex + 1)..];
+                name = name[..equalsIndex];
+            }
+            else
+            {
+                if (index + 1 >= args.Count || args[index + 1].StartsWith("--", StringComparison.Ordinal))
+                {
+                    return ApiKeyAdminParseResult.Fail($"Option '--{name}' requires a value.");
+                }
+
+                value = args[++index];
+            }
+
+            options[name] = value;
+        }
+
+        string? keyId = GetOption(options, "key-id");
+        string? displayName = GetOption(options, "display-name");
+        IReadOnlySet<string> scopes = ParseScopes(GetOption(options, "scopes"));
+
+        string? validationError = Validate(kind, keyId, displayName);
+        if (validationError is not null)
+        {
+            return ApiKeyAdminParseResult.Fail(validationError);
+        }
+
+        return ApiKeyAdminParseResult.Success(new ApiKeyAdminCommand(
+            Kind: kind,
+            Json: json,
+            SqlitePath: GetOption(options, "sqlite-path"),
+            Pepper: GetOption(options, "pepper"),
+            KeyId: keyId,
+            DisplayName: displayName,
+            Scopes: scopes));
+    }
+
+    private static bool TryParseKind(string value, out ApiKeyAdminCommandKind kind)
+    {
+        switch (value.ToLowerInvariant())
+        {
+            case "init-db":
+                kind = ApiKeyAdminCommandKind.InitDb;
+                return true;
+            case "create-key":
+                kind = ApiKeyAdminCommandKind.CreateKey;
+                return true;
+            case "list-keys":
+                kind = ApiKeyAdminCommandKind.ListKeys;
+                return true;
+            case "revoke-key":
+                kind = ApiKeyAdminCommandKind.RevokeKey;
+                return true;
+            case "rotate-key":
+                kind = ApiKeyAdminCommandKind.RotateKey;
+                return true;
+            default:
+                kind = default;
+                return false;
+        }
+    }
+
+    private static string? Validate(ApiKeyAdminCommandKind kind, string? keyId, string? displayName)
+    {
+        if (kind is ApiKeyAdminCommandKind.CreateKey or ApiKeyAdminCommandKind.RevokeKey or ApiKeyAdminCommandKind.RotateKey
+            && string.IsNullOrWhiteSpace(keyId))
+        {
+            return $"Subcommand '{KindName(kind)}' requires --key-id.";
+        }
+
+        if (!string.IsNullOrWhiteSpace(keyId) && !IsValidKeyId(keyId))
+        {
+            return "API key id may contain only letters, numbers, periods, and hyphens.";
+        }
+
+        if (kind == ApiKeyAdminCommandKind.CreateKey && string.IsNullOrWhiteSpace(displayName))
+        {
+            return "Subcommand 'create-key' requires --display-name.";
+        }
+
+        return null;
+    }
+
+    private static string KindName(ApiKeyAdminCommandKind kind)
+    {
+        return kind switch
+        {
+            ApiKeyAdminCommandKind.InitDb => "init-db",
+            ApiKeyAdminCommandKind.CreateKey => "create-key",
+            ApiKeyAdminCommandKind.ListKeys => "list-keys",
+            ApiKeyAdminCommandKind.RevokeKey => "revoke-key",
+            ApiKeyAdminCommandKind.RotateKey => "rotate-key",
+            _ => kind.ToString()
+        };
+    }
+
+    private static bool IsValidKeyId(string keyId)
+    {
+        return keyId.All(character =>
+            char.IsAsciiLetterOrDigit(character)
+            || character is '.' or '-');
+    }
+
+    private static string? GetOption(Dictionary<string, string?> options, string name)
+    {
+        return options.TryGetValue(name, out string? value) ? value : null;
+    }
+
+    private static IReadOnlySet<string> ParseScopes(string? scopes)
+    {
+        return new HashSet<string>(
+            (scopes ?? string.Empty)
+                .Split(',', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries),
+            StringComparer.Ordinal);
+    }
+}

src/MxGateway.Server/Security/Authentication/ApiKeyAdminListedKey.cs

@@ -0,0 +1,10 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed record ApiKeyAdminListedKey(
+    string KeyId,
+    string KeyPrefix,
+    string DisplayName,
+    IReadOnlySet<string> Scopes,
+    DateTimeOffset CreatedUtc,
+    DateTimeOffset? LastUsedUtc,
+    DateTimeOffset? RevokedUtc);

src/MxGateway.Server/Security/Authentication/ApiKeyAdminOutput.cs

@@ -0,0 +1,7 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed record ApiKeyAdminOutput(
+    string Command,
+    string Status,
+    string? ApiKey,
+    IReadOnlyList<ApiKeyAdminListedKey> Keys);

src/MxGateway.Server/Security/Authentication/ApiKeyAdminParseResult.cs

@@ -0,0 +1,22 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed record ApiKeyAdminParseResult(
+    bool IsApiKeyCommand,
+    ApiKeyAdminCommand? Command,
+    string? Error)
+{
+    public static ApiKeyAdminParseResult NotApiKeyCommand()
+    {
+        return new ApiKeyAdminParseResult(false, null, null);
+    }
+
+    public static ApiKeyAdminParseResult Success(ApiKeyAdminCommand command)
+    {
+        return new ApiKeyAdminParseResult(true, command, null);
+    }
+
+    public static ApiKeyAdminParseResult Fail(string error)
+    {
+        return new ApiKeyAdminParseResult(true, null, error);
+    }
+}

src/MxGateway.Server/Security/Authentication/ApiKeyCreateRequest.cs

@@ -0,0 +1,9 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed record ApiKeyCreateRequest(
+    string KeyId,
+    string KeyPrefix,
+    byte[] SecretHash,
+    string DisplayName,
+    IReadOnlySet<string> Scopes,
+    DateTimeOffset CreatedUtc);

src/MxGateway.Server/Security/Authentication/ApiKeyRecordReader.cs

@@ -0,0 +1,26 @@
+using Microsoft.Data.Sqlite;
+
+namespace MxGateway.Server.Security.Authentication;
+
+public static class ApiKeyRecordReader
+{
+    public static ApiKeyRecord Read(SqliteDataReader reader)
+    {
+        return new ApiKeyRecord(
+            KeyId: reader.GetString(0),
+            KeyPrefix: reader.GetString(1),
+            SecretHash: (byte[])reader["secret_hash"],
+            DisplayName: reader.GetString(3),
+            Scopes: ApiKeyScopeSerializer.Deserialize(reader.GetString(4)),
+            CreatedUtc: DateTimeOffset.Parse(reader.GetString(5), System.Globalization.CultureInfo.InvariantCulture),
+            LastUsedUtc: ReadNullableDateTimeOffset(reader, 6),
+            RevokedUtc: ReadNullableDateTimeOffset(reader, 7));
+    }
+
+    private static DateTimeOffset? ReadNullableDateTimeOffset(SqliteDataReader reader, int ordinal)
+    {
+        return reader.IsDBNull(ordinal)
+            ? null
+            : DateTimeOffset.Parse(reader.GetString(ordinal), System.Globalization.CultureInfo.InvariantCulture);
+    }
+}

src/MxGateway.Server/Security/Authentication/ApiKeySecretGenerator.cs

@@ -0,0 +1,17 @@
+using System.Security.Cryptography;
+
+namespace MxGateway.Server.Security.Authentication;
+
+public static class ApiKeySecretGenerator
+{
+    public static string Generate()
+    {
+        Span<byte> bytes = stackalloc byte[32];
+        RandomNumberGenerator.Fill(bytes);
+
+        return Convert.ToBase64String(bytes)
+            .TrimEnd('=')
+            .Replace('+', '-')
+            .Replace('/', '_');
+    }
+}

src/MxGateway.Server/Security/Authentication/AuthStoreServiceCollectionExtensions.cs

@@ -7,9 +7,11 @@ public static class AuthStoreServiceCollectionExtensions
         services.AddSingleton<IApiKeyParser, ApiKeyParser>();
         services.AddSingleton<IApiKeySecretHasher, ApiKeySecretHasher>();
         services.AddSingleton<IApiKeyVerifier, ApiKeyVerifier>();
+        services.AddSingleton<ApiKeyAdminCliRunner>();
         services.AddSingleton<AuthSqliteConnectionFactory>();
         services.AddSingleton<IAuthStoreMigrator, SqliteAuthStoreMigrator>();
         services.AddSingleton<IApiKeyStore, SqliteApiKeyStore>();
+        services.AddSingleton<IApiKeyAdminStore, SqliteApiKeyAdminStore>();
         services.AddSingleton<IApiKeyAuditStore, SqliteApiKeyAuditStore>();
         services.AddHostedService<AuthStoreMigrationHostedService>();
 

src/MxGateway.Server/Security/Authentication/IApiKeyAdminStore.cs

@@ -0,0 +1,16 @@
+namespace MxGateway.Server.Security.Authentication;
+
+public interface IApiKeyAdminStore
+{
+    Task CreateAsync(ApiKeyCreateRequest request, CancellationToken cancellationToken);
+
+    Task<IReadOnlyList<ApiKeyRecord>> ListAsync(CancellationToken cancellationToken);
+
+    Task<bool> RevokeAsync(string keyId, DateTimeOffset revokedUtc, CancellationToken cancellationToken);
+
+    Task<bool> RotateAsync(
+        string keyId,
+        byte[] secretHash,
+        DateTimeOffset rotatedUtc,
+        CancellationToken cancellationToken);
+}

src/MxGateway.Server/Security/Authentication/SqliteApiKeyAdminStore.cs

@@ -0,0 +1,116 @@
+using Microsoft.Data.Sqlite;
+
+namespace MxGateway.Server.Security.Authentication;
+
+public sealed class SqliteApiKeyAdminStore(AuthSqliteConnectionFactory connectionFactory) : IApiKeyAdminStore
+{
+    public async Task CreateAsync(ApiKeyCreateRequest request, CancellationToken cancellationToken)
+    {
+        await using SqliteConnection connection = connectionFactory.CreateConnection();
+        await connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+
+        await using SqliteCommand command = connection.CreateCommand();
+        command.CommandText = """
+            INSERT INTO api_keys (
+                key_id,
+                key_prefix,
+                secret_hash,
+                display_name,
+                scopes,
+                created_utc,
+                last_used_utc,
+                revoked_utc)
+            VALUES (
+                $key_id,
+                $key_prefix,
+                $secret_hash,
+                $display_name,
+                $scopes,
+                $created_utc,
+                NULL,
+                NULL);
+            """;
+        AddCreateParameters(command, request);
+
+        await command.ExecuteNonQueryAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    public async Task<IReadOnlyList<ApiKeyRecord>> ListAsync(CancellationToken cancellationToken)
+    {
+        await using SqliteConnection connection = connectionFactory.CreateConnection();
+        await connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+
+        await using SqliteCommand command = connection.CreateCommand();
+        command.CommandText = """
+            SELECT key_id, key_prefix, secret_hash, display_name, scopes, created_utc, last_used_utc, revoked_utc
+            FROM api_keys
+            ORDER BY key_id;
+            """;
+
+        List<ApiKeyRecord> records = [];
+
+        await using SqliteDataReader reader = await command.ExecuteReaderAsync(cancellationToken)
+            .ConfigureAwait(false);
+
+        while (await reader.ReadAsync(cancellationToken).ConfigureAwait(false))
+        {
+            records.Add(ApiKeyRecordReader.Read(reader));
+        }
+
+        return records;
+    }
+
+    public async Task<bool> RevokeAsync(string keyId, DateTimeOffset revokedUtc, CancellationToken cancellationToken)
+    {
+        await using SqliteConnection connection = connectionFactory.CreateConnection();
+        await connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+
+        await using SqliteCommand command = connection.CreateCommand();
+        command.CommandText = """
+            UPDATE api_keys
+            SET revoked_utc = $revoked_utc
+            WHERE key_id = $key_id AND revoked_utc IS NULL;
+            """;
+        command.Parameters.AddWithValue("$key_id", keyId);
+        command.Parameters.AddWithValue("$revoked_utc", revokedUtc.ToString("O"));
+
+        int rows = await command.ExecuteNonQueryAsync(cancellationToken).ConfigureAwait(false);
+
+        return rows > 0;
+    }
+
+    public async Task<bool> RotateAsync(
+        string keyId,
+        byte[] secretHash,
+        DateTimeOffset rotatedUtc,
+        CancellationToken cancellationToken)
+    {
+        await using SqliteConnection connection = connectionFactory.CreateConnection();
+        await connection.OpenAsync(cancellationToken).ConfigureAwait(false);
+
+        await using SqliteCommand command = connection.CreateCommand();
+        command.CommandText = """
+            UPDATE api_keys
+            SET secret_hash = $secret_hash,
+                last_used_utc = NULL,
+                revoked_utc = NULL
+            WHERE key_id = $key_id;
+            """;
+        command.Parameters.AddWithValue("$key_id", keyId);
+        command.Parameters.Add("$secret_hash", SqliteType.Blob).Value = secretHash;
+
+        int rows = await command.ExecuteNonQueryAsync(cancellationToken).ConfigureAwait(false);
+
+        return rows > 0;
+    }
+
+    private static void AddCreateParameters(SqliteCommand command, ApiKeyCreateRequest request)
+    {
+        command.Parameters.AddWithValue("$key_id", request.KeyId);
+        command.Parameters.AddWithValue("$key_prefix", request.KeyPrefix);
+        command.Parameters.Add("$secret_hash", SqliteType.Blob).Value = request.SecretHash;
+        command.Parameters.AddWithValue("$display_name", request.DisplayName);
+        command.Parameters.AddWithValue("$scopes", ApiKeyScopeSerializer.Serialize(request.Scopes));
+        command.Parameters.AddWithValue("$created_utc", request.CreatedUtc.ToString("O"));
+    }
+}

src/MxGateway.Server/Security/Authentication/SqliteApiKeyStore.cs

@@ -61,26 +61,6 @@ public sealed class SqliteApiKeyStore(AuthSqliteConnectionFactory connectionFact
             return null;
         }
 
-        return ReadApiKeyRecord(reader);
-    }
-
-    private static ApiKeyRecord ReadApiKeyRecord(SqliteDataReader reader)
-    {
-        return new ApiKeyRecord(
-            KeyId: reader.GetString(0),
-            KeyPrefix: reader.GetString(1),
-            SecretHash: (byte[])reader["secret_hash"],
-            DisplayName: reader.GetString(3),
-            Scopes: ApiKeyScopeSerializer.Deserialize(reader.GetString(4)),
-            CreatedUtc: DateTimeOffset.Parse(reader.GetString(5), System.Globalization.CultureInfo.InvariantCulture),
-            LastUsedUtc: ReadNullableDateTimeOffset(reader, 6),
-            RevokedUtc: ReadNullableDateTimeOffset(reader, 7));
-    }
-
-    private static DateTimeOffset? ReadNullableDateTimeOffset(SqliteDataReader reader, int ordinal)
-    {
-        return reader.IsDBNull(ordinal)
-            ? null
-            : DateTimeOffset.Parse(reader.GetString(ordinal), System.Globalization.CultureInfo.InvariantCulture);
+        return ApiKeyRecordReader.Read(reader);
     }
 }

src/MxGateway.Server/Security/Authorization/GatewayGrpcAuthorizationInterceptor.cs

@@ -0,0 +1,74 @@
+using Grpc.Core;
+using Grpc.Core.Interceptors;
+using Microsoft.Extensions.Options;
+using MxGateway.Server.Configuration;
+using MxGateway.Server.Security.Authentication;
+
+namespace MxGateway.Server.Security.Authorization;
+
+public sealed class GatewayGrpcAuthorizationInterceptor(
+    IApiKeyVerifier apiKeyVerifier,
+    GatewayGrpcScopeResolver scopeResolver,
+    IGatewayRequestIdentityAccessor identityAccessor,
+    IOptions<GatewayOptions> options) : Interceptor
+{
+    public override async Task<TResponse> UnaryServerHandler<TRequest, TResponse>(
+        TRequest request,
+        ServerCallContext context,
+        UnaryServerMethod<TRequest, TResponse> continuation)
+    {
+        ApiKeyIdentity? identity = await AuthenticateAndAuthorizeAsync(request, context).ConfigureAwait(false);
+        IDisposable? identityScope = identity is null ? null : identityAccessor.Push(identity);
+        using (identityScope)
+        {
+            return await continuation(request, context).ConfigureAwait(false);
+        }
+    }
+
+    public override async Task ServerStreamingServerHandler<TRequest, TResponse>(
+        TRequest request,
+        IServerStreamWriter<TResponse> responseStream,
+        ServerCallContext context,
+        ServerStreamingServerMethod<TRequest, TResponse> continuation)
+    {
+        ApiKeyIdentity? identity = await AuthenticateAndAuthorizeAsync(request, context).ConfigureAwait(false);
+        IDisposable? identityScope = identity is null ? null : identityAccessor.Push(identity);
+        using (identityScope)
+        {
+            await continuation(request, responseStream, context).ConfigureAwait(false);
+        }
+    }
+
+    private async Task<ApiKeyIdentity?> AuthenticateAndAuthorizeAsync<TRequest>(
+        TRequest request,
+        ServerCallContext context)
+        where TRequest : class
+    {
+        if (options.Value.Authentication.Mode == AuthenticationMode.Disabled)
+        {
+            return null;
+        }
+
+        string? authorizationHeader = context.RequestHeaders.GetValue("authorization");
+        ApiKeyVerificationResult verificationResult = await apiKeyVerifier
+            .VerifyAsync(authorizationHeader, context.CancellationToken)
+            .ConfigureAwait(false);
+
+        if (!verificationResult.Succeeded || verificationResult.Identity is null)
+        {
+            throw new RpcException(new Status(
+                StatusCode.Unauthenticated,
+                "Missing or invalid API key."));
+        }
+
+        string requiredScope = scopeResolver.ResolveRequiredScope(request);
+        if (!verificationResult.Identity.Scopes.Contains(requiredScope))
+        {
+            throw new RpcException(new Status(
+                StatusCode.PermissionDenied,
+                $"API key is missing required scope '{requiredScope}'."));
+        }
+
+        return verificationResult.Identity;
+    }
+}

src/MxGateway.Server/Security/Authorization/GatewayGrpcScopeResolver.cs

@@ -0,0 +1,40 @@
+using MxGateway.Contracts.Proto;
+
+namespace MxGateway.Server.Security.Authorization;
+
+public sealed class GatewayGrpcScopeResolver
+{
+    public string ResolveRequiredScope(object request)
+    {
+        return request switch
+        {
+            OpenSessionRequest => GatewayScopes.SessionOpen,
+            CloseSessionRequest => GatewayScopes.SessionClose,
+            StreamEventsRequest => GatewayScopes.EventsRead,
+            MxCommandRequest commandRequest => ResolveCommandScope(commandRequest.Command?.Kind ?? MxCommandKind.Unspecified),
+            _ => GatewayScopes.Admin
+        };
+    }
+
+    private static string ResolveCommandScope(MxCommandKind kind)
+    {
+        return kind switch
+        {
+            MxCommandKind.Write or
+            MxCommandKind.Write2 => GatewayScopes.InvokeWrite,
+
+            MxCommandKind.WriteSecured or
+            MxCommandKind.WriteSecured2 or
+            MxCommandKind.AuthenticateUser => GatewayScopes.InvokeSecure,
+
+            MxCommandKind.ArchestraUserToId or
+            MxCommandKind.GetSessionState or
+            MxCommandKind.GetWorkerInfo => GatewayScopes.MetadataRead,
+
+            MxCommandKind.DrainEvents => GatewayScopes.EventsRead,
+            MxCommandKind.ShutdownWorker => GatewayScopes.Admin,
+
+            _ => GatewayScopes.InvokeRead
+        };
+    }
+}

src/MxGateway.Server/Security/Authorization/GatewayRequestIdentityAccessor.cs

@@ -0,0 +1,38 @@
+using MxGateway.Server.Security.Authentication;
+
+namespace MxGateway.Server.Security.Authorization;
+
+public sealed class GatewayRequestIdentityAccessor : IGatewayRequestIdentityAccessor
+{
+    private readonly AsyncLocal<ApiKeyIdentity?> currentIdentity = new();
+
+    public ApiKeyIdentity? Current => currentIdentity.Value;
+
+    public IDisposable Push(ApiKeyIdentity identity)
+    {
+        ArgumentNullException.ThrowIfNull(identity);
+
+        ApiKeyIdentity? previousIdentity = currentIdentity.Value;
+        currentIdentity.Value = identity;
+
+        return new IdentityScope(this, previousIdentity);
+    }
+
+    private sealed class IdentityScope(
+        GatewayRequestIdentityAccessor accessor,
+        ApiKeyIdentity? previousIdentity) : IDisposable
+    {
+        private bool disposed;
+
+        public void Dispose()
+        {
+            if (disposed)
+            {
+                return;
+            }
+
+            accessor.currentIdentity.Value = previousIdentity;
+            disposed = true;
+        }
+    }
+}

src/MxGateway.Server/Security/Authorization/GatewayScopes.cs

@@ -0,0 +1,13 @@
+namespace MxGateway.Server.Security.Authorization;
+
+public static class GatewayScopes
+{
+    public const string SessionOpen = "session:open";
+    public const string SessionClose = "session:close";
+    public const string InvokeRead = "invoke:read";
+    public const string InvokeWrite = "invoke:write";
+    public const string InvokeSecure = "invoke:secure";
+    public const string EventsRead = "events:read";
+    public const string MetadataRead = "metadata:read";
+    public const string Admin = "admin";
+}

src/MxGateway.Server/Security/Authorization/GrpcAuthorizationServiceCollectionExtensions.cs

@@ -0,0 +1,16 @@
+using Grpc.Core.Interceptors;
+
+namespace MxGateway.Server.Security.Authorization;
+
+public static class GrpcAuthorizationServiceCollectionExtensions
+{
+    public static IServiceCollection AddGatewayGrpcAuthorization(this IServiceCollection services)
+    {
+        services.AddSingleton<GatewayGrpcScopeResolver>();
+        services.AddSingleton<IGatewayRequestIdentityAccessor, GatewayRequestIdentityAccessor>();
+        services.AddSingleton<GatewayGrpcAuthorizationInterceptor>();
+        services.AddGrpc(options => options.Interceptors.Add<GatewayGrpcAuthorizationInterceptor>());
+
+        return services;
+    }
+}

src/MxGateway.Server/Security/Authorization/IGatewayRequestIdentityAccessor.cs

@@ -0,0 +1,10 @@
+using MxGateway.Server.Security.Authentication;
+
+namespace MxGateway.Server.Security.Authorization;
+
+public interface IGatewayRequestIdentityAccessor
+{
+    ApiKeyIdentity? Current { get; }
+
+    IDisposable Push(ApiKeyIdentity identity);
+}

src/MxGateway.Tests/Security/Authentication/ApiKeyAdminCliRunnerTests.cs

@@ -0,0 +1,242 @@
+using System.Text.Json;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using MxGateway.Server.Configuration;
+using MxGateway.Server.Security.Authentication;
+
+namespace MxGateway.Tests.Security.Authentication;
+
+public sealed class ApiKeyAdminCliRunnerTests
+{
+    [Fact]
+    public async Task CreateKeyAsync_CreatesAuthenticatingKeyAndAudits()
+    {
+        await using ServiceProvider services = BuildServices(CreateTempDatabasePath());
+        ApiKeyAdminCliRunner runner = services.GetRequiredService<ApiKeyAdminCliRunner>();
+        StringWriter output = new();
+
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.CreateKey,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: "operator01",
+                DisplayName: "Operator",
+                Scopes: new HashSet<string>(StringComparer.Ordinal) { "session:open", "events:read" }),
+            output,
+            CancellationToken.None);
+
+        string apiKey = ReadApiKey(output.ToString());
+
+        IApiKeyVerifier verifier = services.GetRequiredService<IApiKeyVerifier>();
+        ApiKeyVerificationResult verification = await verifier.VerifyAsync($"Bearer {apiKey}", CancellationToken.None);
+
+        Assert.True(verification.Succeeded);
+        Assert.NotNull(verification.Identity);
+        Assert.Equal("operator01", verification.Identity.KeyId);
+        Assert.Contains("session:open", verification.Identity.Scopes);
+
+        IReadOnlyList<ApiKeyAuditRecord> auditRecords = await services
+            .GetRequiredService<IApiKeyAuditStore>()
+            .ListRecentAsync(10, CancellationToken.None);
+
+        Assert.Contains(auditRecords, record => record.EventType == "create-key" && record.KeyId == "operator01");
+    }
+
+    [Fact]
+    public async Task ListKeysAsync_DoesNotPrintRawSecret()
+    {
+        await using ServiceProvider services = BuildServices(CreateTempDatabasePath());
+        ApiKeyAdminCliRunner runner = services.GetRequiredService<ApiKeyAdminCliRunner>();
+        string apiKey = await CreateKeyAsync(runner, "operator01");
+        StringWriter listOutput = new();
+
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.ListKeys,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: null,
+                DisplayName: null,
+                Scopes: new HashSet<string>(StringComparer.Ordinal)),
+            listOutput,
+            CancellationToken.None);
+
+        string listJson = listOutput.ToString();
+
+        Assert.Contains("operator01", listJson, StringComparison.Ordinal);
+        Assert.DoesNotContain(apiKey, listJson, StringComparison.Ordinal);
+        Assert.DoesNotContain(ApiKeySecret(apiKey), listJson, StringComparison.Ordinal);
+        Assert.DoesNotContain("secret_hash", listJson, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task RevokeKeyAsync_RevokedKeyFailsVerificationAndAudits()
+    {
+        await using ServiceProvider services = BuildServices(CreateTempDatabasePath());
+        ApiKeyAdminCliRunner runner = services.GetRequiredService<ApiKeyAdminCliRunner>();
+        string apiKey = await CreateKeyAsync(runner, "operator01");
+
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.RevokeKey,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: "operator01",
+                DisplayName: null,
+                Scopes: new HashSet<string>(StringComparer.Ordinal)),
+            TextWriter.Null,
+            CancellationToken.None);
+
+        ApiKeyVerificationResult verification = await services
+            .GetRequiredService<IApiKeyVerifier>()
+            .VerifyAsync($"Bearer {apiKey}", CancellationToken.None);
+
+        Assert.False(verification.Succeeded);
+        Assert.Equal(ApiKeyVerificationFailure.KeyRevoked, verification.Failure);
+
+        IReadOnlyList<ApiKeyAuditRecord> auditRecords = await services
+            .GetRequiredService<IApiKeyAuditStore>()
+            .ListRecentAsync(10, CancellationToken.None);
+
+        Assert.Contains(auditRecords, record => record.EventType == "revoke-key" && record.KeyId == "operator01");
+    }
+
+    [Fact]
+    public async Task RotateKeyAsync_PrintsNewSecretOnceAndInvalidatesOldSecret()
+    {
+        await using ServiceProvider services = BuildServices(CreateTempDatabasePath());
+        ApiKeyAdminCliRunner runner = services.GetRequiredService<ApiKeyAdminCliRunner>();
+        string oldApiKey = await CreateKeyAsync(runner, "operator01");
+        StringWriter rotateOutput = new();
+
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.RotateKey,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: "operator01",
+                DisplayName: null,
+                Scopes: new HashSet<string>(StringComparer.Ordinal)),
+            rotateOutput,
+            CancellationToken.None);
+
+        string rotateJson = rotateOutput.ToString();
+        string newApiKey = ReadApiKey(rotateJson);
+
+        Assert.NotEqual(oldApiKey, newApiKey);
+        Assert.Equal(1, CountOccurrences(rotateJson, newApiKey));
+
+        IApiKeyVerifier verifier = services.GetRequiredService<IApiKeyVerifier>();
+        ApiKeyVerificationResult oldVerification = await verifier.VerifyAsync($"Bearer {oldApiKey}", CancellationToken.None);
+        ApiKeyVerificationResult newVerification = await verifier.VerifyAsync($"Bearer {newApiKey}", CancellationToken.None);
+
+        Assert.False(oldVerification.Succeeded);
+        Assert.Equal(ApiKeyVerificationFailure.SecretMismatch, oldVerification.Failure);
+        Assert.True(newVerification.Succeeded);
+    }
+
+    [Fact]
+    public async Task CreateKeyAsync_PrintsRawSecretExactlyOnce()
+    {
+        await using ServiceProvider services = BuildServices(CreateTempDatabasePath());
+        ApiKeyAdminCliRunner runner = services.GetRequiredService<ApiKeyAdminCliRunner>();
+        StringWriter output = new();
+
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.CreateKey,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: "operator01",
+                DisplayName: "Operator",
+                Scopes: new HashSet<string>(StringComparer.Ordinal)),
+            output,
+            CancellationToken.None);
+
+        string json = output.ToString();
+        string apiKey = ReadApiKey(json);
+
+        Assert.Equal(1, CountOccurrences(json, apiKey));
+        Assert.Equal(1, CountOccurrences(json, ApiKeySecret(apiKey)));
+    }
+
+    private static async Task<string> CreateKeyAsync(ApiKeyAdminCliRunner runner, string keyId)
+    {
+        StringWriter output = new();
+        await runner.RunAsync(
+            new ApiKeyAdminCommand(
+                Kind: ApiKeyAdminCommandKind.CreateKey,
+                Json: true,
+                SqlitePath: null,
+                Pepper: null,
+                KeyId: keyId,
+                DisplayName: "Operator",
+                Scopes: new HashSet<string>(StringComparer.Ordinal) { "session:open" }),
+            output,
+            CancellationToken.None);
+
+        return ReadApiKey(output.ToString());
+    }
+
+    private static ServiceProvider BuildServices(string databasePath)
+    {
+        IConfigurationRoot configuration = new ConfigurationBuilder()
+            .AddInMemoryCollection(
+                new Dictionary<string, string?>
+                {
+                    ["MxGateway:Authentication:SqlitePath"] = databasePath,
+                    ["MxGateway:ApiKeyPepper"] = "test-pepper"
+                })
+            .Build();
+
+        ServiceCollection services = new();
+        services.AddSingleton<IConfiguration>(configuration);
+        services.AddGatewayConfiguration();
+        services.AddSqliteAuthStore();
+
+        return services.BuildServiceProvider(validateScopes: true);
+    }
+
+    private static string CreateTempDatabasePath()
+    {
+        string directory = Path.Combine(Path.GetTempPath(), "mxgateway-auth-cli-tests", Guid.NewGuid().ToString("N"));
+        Directory.CreateDirectory(directory);
+
+        return Path.Combine(directory, "gateway-auth.db");
+    }
+
+    private static string ReadApiKey(string json)
+    {
+        using JsonDocument document = JsonDocument.Parse(json);
+
+        return document.RootElement.GetProperty("ApiKey").GetString()
+            ?? throw new InvalidOperationException("API key was not present in command output.");
+    }
+
+    private static string ApiKeySecret(string apiKey)
+    {
+        string[] parts = apiKey.Split('_', 3);
+
+        return parts[2];
+    }
+
+    private static int CountOccurrences(string value, string pattern)
+    {
+        int count = 0;
+        int index = 0;
+
+        while ((index = value.IndexOf(pattern, index, StringComparison.Ordinal)) >= 0)
+        {
+            count++;
+            index += pattern.Length;
+        }
+
+        return count;
+    }
+}

src/MxGateway.Tests/Security/Authentication/ApiKeyAdminCommandLineParserTests.cs

@@ -0,0 +1,70 @@
+using MxGateway.Server.Security.Authentication;
+
+namespace MxGateway.Tests.Security.Authentication;
+
+public sealed class ApiKeyAdminCommandLineParserTests
+{
+    [Fact]
+    public void Parse_NonApiKeyCommand_ReturnsNotApiKeyCommand()
+    {
+        ApiKeyAdminParseResult result = ApiKeyAdminCommandLineParser.Parse(["--urls=http://localhost:5000"]);
+
+        Assert.False(result.IsApiKeyCommand);
+        Assert.Null(result.Command);
+    }
+
+    [Fact]
+    public void Parse_CreateKeyCommand_ReturnsOptions()
+    {
+        ApiKeyAdminParseResult result = ApiKeyAdminCommandLineParser.Parse(
+            [
+                "apikey",
+                "create-key",
+                "--key-id",
+                "operator01",
+                "--display-name",
+                "Operator",
+                "--scopes",
+                "session:open,events:read",
+                "--sqlite-path",
+                "auth.db",
+                "--pepper",
+                "pepper",
+                "--json"
+            ]);
+
+        Assert.True(result.IsApiKeyCommand);
+        Assert.Null(result.Error);
+        Assert.NotNull(result.Command);
+        Assert.Equal(ApiKeyAdminCommandKind.CreateKey, result.Command.Kind);
+        Assert.True(result.Command.Json);
+        Assert.Equal("operator01", result.Command.KeyId);
+        Assert.Equal("Operator", result.Command.DisplayName);
+        Assert.Equal("auth.db", result.Command.SqlitePath);
+        Assert.Equal("pepper", result.Command.Pepper);
+        Assert.Contains("session:open", result.Command.Scopes);
+        Assert.Contains("events:read", result.Command.Scopes);
+    }
+
+    [Fact]
+    public void Parse_CreateKeyWithoutDisplayName_ReturnsError()
+    {
+        ApiKeyAdminParseResult result = ApiKeyAdminCommandLineParser.Parse(
+            ["apikey", "create-key", "--key-id", "operator01"]);
+
+        Assert.True(result.IsApiKeyCommand);
+        Assert.Null(result.Command);
+        Assert.Contains("--display-name", result.Error, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void Parse_KeyIdWithUnderscore_ReturnsError()
+    {
+        ApiKeyAdminParseResult result = ApiKeyAdminCommandLineParser.Parse(
+            ["apikey", "revoke-key", "--key-id", "operator_01"]);
+
+        Assert.True(result.IsApiKeyCommand);
+        Assert.Null(result.Command);
+        Assert.Contains("letters, numbers, periods, and hyphens", result.Error, StringComparison.Ordinal);
+    }
+}

src/MxGateway.Tests/Security/Authorization/GatewayGrpcAuthorizationInterceptorTests.cs

@@ -0,0 +1,267 @@
+using Grpc.Core;
+using Microsoft.Extensions.Options;
+using MxGateway.Contracts.Proto;
+using MxGateway.Server.Configuration;
+using MxGateway.Server.Security.Authentication;
+using MxGateway.Server.Security.Authorization;
+
+namespace MxGateway.Tests.Security.Authorization;
+
+public sealed class GatewayGrpcAuthorizationInterceptorTests
+{
+    [Fact]
+    public async Task UnaryServerHandler_MissingApiKey_ReturnsUnauthenticated()
+    {
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(ApiKeyVerificationResult.Fail(
+                ApiKeyVerificationFailure.MissingOrMalformedCredentials)),
+            new GatewayRequestIdentityAccessor());
+
+        RpcException exception = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.UnaryServerHandler(
+                new OpenSessionRequest(),
+                new TestServerCallContext([]),
+                (_, _) => Task.FromResult(new OpenSessionReply())));
+
+        Assert.Equal(StatusCode.Unauthenticated, exception.StatusCode);
+        Assert.DoesNotContain("secret", exception.Status.Detail, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task UnaryServerHandler_InvalidApiKey_DoesNotExposeRawCredentialInStatus()
+    {
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(ApiKeyVerificationResult.Fail(ApiKeyVerificationFailure.SecretMismatch)),
+            new GatewayRequestIdentityAccessor());
+
+        RpcException exception = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.UnaryServerHandler(
+                new OpenSessionRequest(),
+                ContextWithAuthorization("Bearer mxgw_operator01_super-secret"),
+                (_, _) => Task.FromResult(new OpenSessionReply())));
+
+        Assert.Equal(StatusCode.Unauthenticated, exception.StatusCode);
+        Assert.DoesNotContain("super-secret", exception.Status.Detail, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task UnaryServerHandler_ValidApiKeyMissingScope_ReturnsPermissionDenied()
+    {
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(SuccessWithScopes(GatewayScopes.EventsRead)),
+            new GatewayRequestIdentityAccessor());
+
+        RpcException exception = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.UnaryServerHandler(
+                new OpenSessionRequest(),
+                ContextWithAuthorization("Bearer mxgw_operator01_secret"),
+                (_, _) => Task.FromResult(new OpenSessionReply())));
+
+        Assert.Equal(StatusCode.PermissionDenied, exception.StatusCode);
+        Assert.Contains(GatewayScopes.SessionOpen, exception.Status.Detail, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task UnaryServerHandler_ValidApiKeyWithScope_SetsRequestIdentity()
+    {
+        GatewayRequestIdentityAccessor identityAccessor = new();
+        ApiKeyIdentity? identitySeenByHandler = null;
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(SuccessWithScopes(GatewayScopes.SessionOpen)),
+            identityAccessor);
+
+        OpenSessionReply reply = await interceptor.UnaryServerHandler(
+            new OpenSessionRequest(),
+            ContextWithAuthorization("Bearer mxgw_operator01_secret"),
+            (_, _) =>
+            {
+                identitySeenByHandler = identityAccessor.Current;
+
+                return Task.FromResult(new OpenSessionReply { SessionId = "session-1" });
+            });
+
+        Assert.Equal("session-1", reply.SessionId);
+        Assert.NotNull(identitySeenByHandler);
+        Assert.Equal("operator01", identitySeenByHandler.KeyId);
+        Assert.Null(identityAccessor.Current);
+    }
+
+    [Fact]
+    public async Task ServerStreamingServerHandler_ValidApiKeyMissingScope_ReturnsPermissionDenied()
+    {
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(SuccessWithScopes(GatewayScopes.SessionOpen)),
+            new GatewayRequestIdentityAccessor());
+
+        RpcException exception = await Assert.ThrowsAsync<RpcException>(
+            () => interceptor.ServerStreamingServerHandler(
+                new StreamEventsRequest(),
+                new TestServerStreamWriter<MxEvent>(),
+                ContextWithAuthorization("Bearer mxgw_operator01_secret"),
+                (_, _, _) => Task.CompletedTask));
+
+        Assert.Equal(StatusCode.PermissionDenied, exception.StatusCode);
+        Assert.Contains(GatewayScopes.EventsRead, exception.Status.Detail, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task ServerStreamingServerHandler_ValidApiKeyWithScope_AllowsStream()
+    {
+        GatewayRequestIdentityAccessor identityAccessor = new();
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            new FakeApiKeyVerifier(SuccessWithScopes(GatewayScopes.EventsRead)),
+            identityAccessor);
+        TestServerStreamWriter<MxEvent> streamWriter = new();
+
+        await interceptor.ServerStreamingServerHandler(
+            new StreamEventsRequest(),
+            streamWriter,
+            ContextWithAuthorization("Bearer mxgw_operator01_secret"),
+            async (_, writer, _) =>
+            {
+                Assert.Equal("operator01", identityAccessor.Current?.KeyId);
+                await writer.WriteAsync(new MxEvent { SessionId = "session-1" });
+            });
+
+        MxEvent eventMessage = Assert.Single(streamWriter.Messages);
+        Assert.Equal("session-1", eventMessage.SessionId);
+        Assert.Null(identityAccessor.Current);
+    }
+
+    [Fact]
+    public async Task UnaryServerHandler_AuthenticationDisabled_SkipsApiKeyVerification()
+    {
+        GatewayRequestIdentityAccessor identityAccessor = new();
+        FakeApiKeyVerifier verifier = new(ApiKeyVerificationResult.Fail(
+            ApiKeyVerificationFailure.MissingOrMalformedCredentials));
+        GatewayGrpcAuthorizationInterceptor interceptor = CreateInterceptor(
+            verifier,
+            identityAccessor,
+            AuthenticationMode.Disabled);
+
+        OpenSessionReply reply = await interceptor.UnaryServerHandler(
+            new OpenSessionRequest(),
+            new TestServerCallContext([]),
+            (_, _) => Task.FromResult(new OpenSessionReply { SessionId = "session-1" }));
+
+        Assert.Equal("session-1", reply.SessionId);
+        Assert.False(verifier.WasCalled);
+        Assert.Null(identityAccessor.Current);
+    }
+
+    private static GatewayGrpcAuthorizationInterceptor CreateInterceptor(
+        IApiKeyVerifier apiKeyVerifier,
+        IGatewayRequestIdentityAccessor identityAccessor,
+        AuthenticationMode authenticationMode = AuthenticationMode.ApiKey)
+    {
+        return new GatewayGrpcAuthorizationInterceptor(
+            apiKeyVerifier,
+            new GatewayGrpcScopeResolver(),
+            identityAccessor,
+            Options.Create(new GatewayOptions
+            {
+                Authentication = new AuthenticationOptions
+                {
+                    Mode = authenticationMode
+                }
+            }));
+    }
+
+    private static ApiKeyVerificationResult SuccessWithScopes(params string[] scopes)
+    {
+        return ApiKeyVerificationResult.Success(new ApiKeyIdentity(
+            KeyId: "operator01",
+            KeyPrefix: "mxgw_operator01",
+            DisplayName: "Operator Key",
+            Scopes: new HashSet<string>(scopes, StringComparer.Ordinal)));
+    }
+
+    private static TestServerCallContext ContextWithAuthorization(string authorizationHeader)
+    {
+        return new TestServerCallContext([new Metadata.Entry("authorization", authorizationHeader)]);
+    }
+
+    private sealed class FakeApiKeyVerifier(ApiKeyVerificationResult result) : IApiKeyVerifier
+    {
+        public bool WasCalled { get; private set; }
+
+        public string? LastAuthorizationHeader { get; private set; }
+
+        public Task<ApiKeyVerificationResult> VerifyAsync(
+            string? authorizationHeader,
+            CancellationToken cancellationToken)
+        {
+            WasCalled = true;
+            LastAuthorizationHeader = authorizationHeader;
+
+            return Task.FromResult(result);
+        }
+    }
+
+    private sealed class TestServerStreamWriter<T> : IServerStreamWriter<T>
+    {
+        public List<T> Messages { get; } = [];
+
+        public WriteOptions? WriteOptions { get; set; }
+
+        public Task WriteAsync(T message)
+        {
+            Messages.Add(message);
+
+            return Task.CompletedTask;
+        }
+    }
+
+    private sealed class TestServerCallContext(
+        Metadata requestHeaders,
+        CancellationToken cancellationToken = default) : ServerCallContext
+    {
+        private readonly Metadata responseTrailers = [];
+        private readonly Dictionary<object, object> userState = [];
+        private Status status;
+        private WriteOptions? writeOptions;
+
+        protected override string MethodCore => "/mxaccess_gateway.v1.MxAccessGateway/Test";
+
+        protected override string HostCore => "localhost";
+
+        protected override string PeerCore => "ipv4:127.0.0.1:5000";
+
+        protected override DateTime DeadlineCore => DateTime.UtcNow.AddMinutes(1);
+
+        protected override Metadata RequestHeadersCore => requestHeaders;
+
+        protected override CancellationToken CancellationTokenCore => cancellationToken;
+
+        protected override Metadata ResponseTrailersCore => responseTrailers;
+
+        protected override Status StatusCore
+        {
+            get => status;
+            set => status = value;
+        }
+
+        protected override WriteOptions? WriteOptionsCore
+        {
+            get => writeOptions;
+            set => writeOptions = value;
+        }
+
+        protected override AuthContext AuthContextCore { get; } = new(
+            string.Empty,
+            new Dictionary<string, List<AuthProperty>>(StringComparer.Ordinal));
+
+        protected override IDictionary<object, object> UserStateCore => userState;
+
+        protected override Task WriteResponseHeadersAsyncCore(Metadata responseHeaders)
+        {
+            return Task.CompletedTask;
+        }
+
+        protected override ContextPropagationToken CreatePropagationTokenCore(
+            ContextPropagationOptions? options)
+        {
+            throw new NotSupportedException();
+        }
+    }
+}

src/MxGateway.Tests/Security/Authorization/GatewayGrpcScopeResolverTests.cs

@@ -0,0 +1,54 @@
+using MxGateway.Contracts.Proto;
+using MxGateway.Server.Security.Authorization;
+
+namespace MxGateway.Tests.Security.Authorization;
+
+public sealed class GatewayGrpcScopeResolverTests
+{
+    [Theory]
+    [InlineData(typeof(OpenSessionRequest), GatewayScopes.SessionOpen)]
+    [InlineData(typeof(CloseSessionRequest), GatewayScopes.SessionClose)]
+    [InlineData(typeof(StreamEventsRequest), GatewayScopes.EventsRead)]
+    public void ResolveRequiredScope_KnownRpcRequest_ReturnsExpectedScope(
+        Type requestType,
+        string expectedScope)
+    {
+        GatewayGrpcScopeResolver resolver = new();
+        object request = Activator.CreateInstance(requestType)!;
+
+        string scope = resolver.ResolveRequiredScope(request);
+
+        Assert.Equal(expectedScope, scope);
+    }
+
+    [Theory]
+    [InlineData(MxCommandKind.Register, GatewayScopes.InvokeRead)]
+    [InlineData(MxCommandKind.AddItem, GatewayScopes.InvokeRead)]
+    [InlineData(MxCommandKind.Advise, GatewayScopes.InvokeRead)]
+    [InlineData(MxCommandKind.Write, GatewayScopes.InvokeWrite)]
+    [InlineData(MxCommandKind.Write2, GatewayScopes.InvokeWrite)]
+    [InlineData(MxCommandKind.WriteSecured, GatewayScopes.InvokeSecure)]
+    [InlineData(MxCommandKind.WriteSecured2, GatewayScopes.InvokeSecure)]
+    [InlineData(MxCommandKind.AuthenticateUser, GatewayScopes.InvokeSecure)]
+    [InlineData(MxCommandKind.ArchestraUserToId, GatewayScopes.MetadataRead)]
+    [InlineData(MxCommandKind.GetSessionState, GatewayScopes.MetadataRead)]
+    [InlineData(MxCommandKind.GetWorkerInfo, GatewayScopes.MetadataRead)]
+    [InlineData(MxCommandKind.DrainEvents, GatewayScopes.EventsRead)]
+    [InlineData(MxCommandKind.ShutdownWorker, GatewayScopes.Admin)]
+    public void ResolveRequiredScope_InvokeCommand_ReturnsExpectedScope(
+        MxCommandKind commandKind,
+        string expectedScope)
+    {
+        GatewayGrpcScopeResolver resolver = new();
+
+        string scope = resolver.ResolveRequiredScope(new MxCommandRequest
+        {
+            Command = new MxCommand
+            {
+                Kind = commandKind
+            }
+        });
+
+        Assert.Equal(expectedScope, scope);
+    }
+}